Topics 1,2,10,11
Which organelles within eukaryotic cells are believed to have originated through endosymbiosis, according to the endosymbiotic theory?
Mitochondria and chloroplasts
were once free-living prokaryotic organisms that were engulfed by a eukaryotic cell, eventually forming a mutually beneficial relationship. This theory explains the double membranes and similarities between these organelles and prokaryotic cells.
Calculate the SA:V ratio of 2 cuboidal cells, one with sides of 4mm (cell A) and the other with sides of 7mm (cell B). Box your answers. Then, using your calculations, determine which cell would be better for long-term storage of materials.
Cell A SA:V = 1.5
Cell B SA:V = 0.86
Cell B is better for long-term storage
Phospholipids are amphipathic. What does this mean?
they are both hydrophobic and hydrophilic
How do hydrophobic molecules pass through the cell membrane? Be specific!
simple diffusion - they do not need assistance passing through the membrane
A red blood cell is placed in a hypertonic solution. What happens to the cell, and what term is used to describe this process?
it loses water through osmosis, causing it to shrink
The movement of a secretory protein in a eukaryotic cell involves several cellular compartments. Using the words from the list below, arrange them in the correct order to represent the pathway for the packaging and processing of a secretory protein.
Nucleus → Rough ER → Golgi → Secretory vesicles → Plasma membrane
A spherical bacterial cell has a radius of 3um. The human egg cell has a radius of 100um.
Which cell is the most efficient at exchanging materials? Provide an explanation
The bacterial cell, because it has the largest surface-to-volume ratio.
What are membrane carbohydrates, like glycolipids, important for?
cell to cell recognition
How can charged particles pass through the plasma membrane? Be specific!
facilitated diffusion - ions have a charge/are hydrophilic so they need assistance passing through the membrane
Identify the 3 ways water will flow (pressure, water potential, and solute concentration)
High to low pressure
high to low water potential
Low to high solute concentration
In eukaryotic cells, what is the primary advantage of compartmentalization with respect to surface area in various organelles?
To maximize the total surface area for cellular functions
Compartmentalization in eukaryotic cells allows for the creation of numerous smaller organelles, each with its own membrane, effectively increasing the surface area available for various cellular functions, including nutrient absorption, which enhances efficiency and cellular processes.
Even though Eukaryotic cells are larger than Prokaryotic cells (10x), how are they able to efficiently transport materials?
membrane-bound organelles and compartmentalization allows for more metabolic relations and efficiency
Many plants have developed an adaptation to withstand harsh winter conditions by increasing the presence of unsaturated phospholipids in their cell membranes. Describe the advantage of this adaptation in cold environments, and how this change in membrane composition aids in the plant's ability to survive the extreme cold.
This makes the membranes more flexible. This ensures that vital processes continue to function efficiently despite the cold, ultimately aiding the plant's survival.
Dialysis tubing was filled with a solution of 95% solvent and 5% solute. The dialysis tubing was placed in a beaker filled with a solution that consisted of 98% solvent and 2% solute.
Predict the movement of solvent. What type of solution is this?
Water will move into the dialysis tubing
Hypotonic solution
The concentration of a NaCl solution is 0.8M. This solution is in a beaker sitting on your desk in the open air. Calculate the solute potential at 23oC.
-47.22 bars.
Provide 3 differences between prokaryotes and eukaryotes
Prokaryotes: Bacteria & Archea, DNA in nucleoid, smaller
Eukaryotes: Fungi/Plants/Animals, DNA in the nucleus, membrane-bound organelles
A team of biologists developed a new drug. One team member hypothesizes that the drug is incapable of freely passing across the plasma membrane and requires the help of membrane proteins to enter cells.
What must be true about the drug if they are correct?
The drug is a large or polar molecule
Why can a high concentration of salts in soil be dangerous to plants?
hypertonic solution
water leaves the plant cell
causes plant cells to shrink --> cause plant to wilt/die
The concentration of a glucose solution is 0.6 M. This solution is in a beaker on your laboratory bench at 25°C. Calculate the solute potential for this glucose solution.
-14.85 bars.
The ______ (Calvin/Krebs) cycle occurs in the _______ (thylakoid/stroma) of the chloroplast.
Calvin / stroma
Even though plants have a cell wall, they can still pass materials through their plasma membrane. Explain how this is possible
Plasmodesmata allows for the exchange of materials between plant cells
What is the difference between a chemical gradient and a concentration gradient?
a concentration gradient refers to the concentration of a particular type of molecule while the chemical gradient refers to the concentration and inconsistency of ions.
If the water potential of a root plant is found to be -5.4 bars, and the water potential of a sucrose solution you place it in is -4.8 bars, which direction will the net flow of water be?
Water will flow from the solution to the root tissue